The main application of the invention is locating the paths followed by veins, for the purpose of extracting varices by various vein-removal techniques, which at present comprise:
either exo-removal of veins performed in various different ways:
by a stripper provided with a ball which "tears out" the vein, disconnecting it from the tissue surrounding the vein: this technique is described in French patent application No. FR 2 133 338 published on Oct. 30, 1972, using "an instrument made of synthetic plastics material, for surgically `rodding` veins";
by devices for exo-removal of veins by means of rings acting in a manner similar to that of a stripper; or
by phlebectomy using a hook which draws the vein through a mini-incision and, by pulling and dissection, brings it to the outside, enabling it to be removed by a varying number of incisions;
or by endo-removal of veins or invaginaton in which the vein is turned insideout like "a glove finger", with the vein being withdrawn by traction applied inside the lumen of the vessel, which method is less traumatizing for nerve structures in the vicinity of the veins. The same principle is applied when removing veins on rods.
Nevertheless, all of those methods encounter a problem of identifying the paths followed by the veins and require dissection, which becomes more difficult with increasing fat, edema, skin state, and the presence of trophic complaints or panniculitis.
At present, to perform such localization, preoperative clinical examination and Doppler echography are used to better locate the paths of veins and to draw them directly on the skin, however these lines drawn on a standing subject are offset during the operation where the patient is reclining, dorsally or ventrally.
Locating techniques are also known in which a point of the body is lighted internally by using optical fibers which are inserted from outside the body into the chosen duct, such as a vein: an external light source is then connected to the end of the fibers situated outside the body, and the fibers guide the light to the other or "distal" end, i.e. the end which has penetrated into said duct and is furthest from said light source, at which point they illuminate the vein around their ends, like a spotlight. One such technique is described in German patent application No. DE 3 603 782 published on Oct. 15, 1987 which teaches a probe comprising firstly a central channel through which liquids can be inserted, and secondly optical fibers distributed around the periphery of the channel and situated in the wall thickness of the probe to provide illumination at the end thereof in the event of a blockage occurring as a surgical instrument for operating in a vein is progressing: it is then possible to locate the position of the blockage from outside the body by transillumination, i.e. by the transmission of light through tissue, and then decide what action to take; that therefore constitutes an instrument for locating a point only, and it cannot be used for extracting varices, neither by exo-removal of veins nor by endo-removal of veins, which require a different instrument such as described above and which specifically could be the instrument which has blocked the vein.